Produção Nacional
Revisado por pares
First Report of Alternaria alternata Causing Leaf Spot on Rumex crispus in Uruguay
2019; American Phytopathological Society; Volume: 103; Issue: 8 Linguagem: Inglês
10.1094/pdis-03-19-0590-pdn
ISSN1943-7692
AutoresTiago Edu Kaspary, Alejandro García, Silvina Stewart, G. Casaroto, Rodrigo Ferraz Ramos, Cristiano Bellé,
Tópico(s)Powdery Mildew Fungal Diseases
ResumoHomePlant DiseaseVol. 103, No. 8First Report of Alternaria alternata Causing Leaf Spot on Rumex crispus in Uruguay PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Alternaria alternata Causing Leaf Spot on Rumex crispus in UruguayT. E. Kaspary, M. A. García, S. Stewart, G. Casaroto, R. F. Ramos, and C. BelléT. E. Kaspary†Corresponding author: T. E. Kaspary; E-mail Address: tkaspary@inia.org.uyhttp://orcid.org/0000-0003-3084-1938Instituto Nacional de Investigación Agropecuaria–INIA, La Estanzuela, Colonia, UruguaySearch for more papers by this author, M. A. GarcíaInstituto Nacional de Investigación Agropecuaria–INIA, La Estanzuela, Colonia, UruguaySearch for more papers by this author, S. Stewarthttp://orcid.org/0000-0003-4472-3422Instituto Nacional de Investigación Agropecuaria–INIA, La Estanzuela, Colonia, UruguaySearch for more papers by this author, G. CasarotoUniversidade Federal do Rio Grande do Sul, Porto Alegre, RS, BrazilSearch for more papers by this author, R. F. Ramoshttp://orcid.org/0000-0002-6414-376XUniversidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul, BrazilSearch for more papers by this author, and C. Belléhttp://orcid.org/0000-0003-2247-3207Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul, BrazilSearch for more papers by this authorAffiliationsAuthors and Affiliations T. E. Kaspary1 † M. A. García1 S. Stewart1 G. Casaroto2 R. F. Ramos3 C. Bellé3 1Instituto Nacional de Investigación Agropecuaria–INIA, La Estanzuela, Colonia, Uruguay 2Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil 3Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul, Brazil Published Online:13 Jun 2019https://doi.org/10.1094/PDIS-03-19-0590-PDNAboutSections ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat Rumex crispus L. (curled dock), a member of the family Polygonaceae, is considered an important weed in grasslands and crops (Hejcman et al. 2012). Curled dock decreases yield and nutritive value of different species by competition for space, water, and nutrients (Zaller 2004). In addition, it may be an alternative host of pests and diseases of crops (Abbasi et al. 2018). In October 2018, R. crispus plants with severe spotting on their leaves were observed in a field at La Estanzuela, in Colonia, a department in southwestern Uruguay. Symptoms were small, circular, light brown spots that eventually turned into irregular, dark brown lesions, although a few remained circular with concentric rings. Leaf lesion samples were surface sterilized (70% ethanol for 30 s, 1% NaClO for 2 min, rinsed three times in sterile water, dried on sterilized filter paper) and placed on potato dextrose agar (PDA). To identify the causal fungus, morphological analysis was conducted, followed by molecular characterization through the amplification and sequencing of the internal transcribed spacer (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), the second largest subunit of RNA polymerase II (RPB2), and the translation elongation factor (TEF-1α) gene regions, using the method described by Woudenberg et al. (2013). Colonies were round, composed of cottony mycelium of dark olivaceous hyphae. Conidiophores were septate, light-to-olive golden brown, with a conidial scar where conidia were produced in long chains. Conidia (n = 50) were obclavate to obpyriform, golden brown, with a cylindrical or coniform beak at the tip, and measured 25.9 to 61.5 μm long × 12.5 to 16.5 μm wide with two to six transverse and one to three longitudinal septa. Sequences of the studied DNA regions were submitted to GenBank, and accession numbers were received (ITS, MK635345; GAPDH, MK639185; RPB2, MK645322; TEF-1α, MK639186). BLAST searches showed 99 to 100% identity with the existing sequences (including ex-type CBS 916.96) of Alternaria alternata (Fr.) Keissl. (1912) (ITS, AF347031; GAPDH, AY278808; RPB2, KC584375; TEF-1α, KC584634). To confirm Koch’s postulates, six plants of R. crispus were inoculated with a suspension of 106 conidia/ml, whereas six plants to which distilled water was applied were considered as controls. All plants were enclosed in plastic bags and incubated in a growth chamber at 25 ± 2°C for 24 h with a 12-h photoperiod. At the end of the 24-h period, plastic bags were removed. Ten days after inoculation, leaves displayed symptoms similar to those observed in the field, whereas controls remained symptomless. The fungus reisolated from inoculated leaves had the same morphological and molecular traits as the initial isolate. Pathogenicity tests were carried out two times. Our findings highlight the relevance of R. crispus as a reservoir for an important crop pathogen as well as a major crop competitor. To our knowledge, this is the first report on A. alternata affecting R. crispus plants in Uruguay.The author(s) declare no conflict of interest.References:Abbasi, P. A., et al. 2018. Can. J. Plant Pathol. 40:451. https://doi.org/10.1080/07060661.2018.1470111 Crossref, ISI, Google ScholarHejcman, M., et al. 2012. J. Pest Sci. 85:191. https://doi.org/10.1007/s10340-012-0414-5 Crossref, ISI, Google ScholarWoudenberg, J. H. C., et al. 2013. Stud. Mycol. 75:171. https://doi.org/10.3114/sim0015 Crossref, ISI, Google ScholarZaller, J. G. 2004. Weed Res. 44:414. https://doi.org/10.1111/j.1365-3180.2004.00416.x Crossref, ISI, Google ScholarThe author(s) declare no conflict of interest.DetailsFiguresLiterature CitedRelated Vol. 103, No. 8 August 2019SubscribeISSN:0191-2917e-ISSN:1943-7692 DownloadCaptionPistachio fruit infected by Neofusicoccum mediterraneum (Moral et al.). Photo credit: T. J. Michailides. Leaf blight on Hosta ventricosa caused by Pseudomonas syringae pv. syringae (Liu et al.). Photo credit: Z. X. Liu. Metrics Article History Issue Date: 1 Aug 2019Published: 13 Jun 2019First Look: 26 Apr 2019Accepted: 24 Apr 2019 Page: 2139 Information© 2019 The American Phytopathological SocietyKeywordsfungifield cropspathogen detectionThe author(s) declare no conflict of interest.Cited byDiagnostic Guide for Alternaria Leaf Spot on Sugar Beet, Red Beet, and ChardSarah Crizon Cortes, Linda Hanson, Laura Miles, Jaime Willbur, and Rachel Naegele14 December 2022 | Plant Health Progress, Vol. 23, No. 4Phytopathogenic fungi with potential as biocontrol agents for weeds of importance in crops of Antioquia, Colombia9 September 2021 | Egyptian Journal of Biological Pest Control, Vol. 31, No. 1
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